1. Field of the Invention
The invention disclosed in this specification relates to a semiconductor device utilizing a semiconductor element and a manufacturing method thereof
2. Description of the Related Art
A technique by which a transistor is formed using a semiconductor thin film formed over a substrate having an insulating surface has attracted attention. The transistor is applied to a wide range of electronic devices such as an integrated circuit (IC) and an image display device (display device). A technique by which a wide-gap semiconductor such as an oxide semiconductor is used for a semiconductor thin film which can be applied to a transistor has attracted attention.
For example, in Patent Document 1, it has been confirmed that an oxide semiconductor containing an In—Ga—Zn-based oxide is applicable to a channel formation region of a thin film transistor.